In industrial process control systems, wireless networks are widely deployed to support sensing and monitoring of industrial processes. Such networks permit industrial processes to be monitored utilizing a wireless sensor without incurring the costs typically associated with wired devices. Such wireless sensors, however, are often required to be compliant with intrinsic safety standards in order to be used in certain applications. For example, wireless sensors may be required to satisfy a “zone 2” (e.g., marginally hazardous) or “zone 0” (e.g., highly hazardous) level of certification.
Wireless sensors typically include an RF (Radio Frequency) or other wireless radio board along with an external antenna for better range performance. For a device to be intrinsically safe, a common constraint is that the antenna's ground and the radio board's ground should be completely isolated by certain distances (e.g., approximately 0.5 mm for “zone 2” and approximately 3.0 mm for “zone 0”). Unfortunately, this type of arrangement disturbs the matching between the antennas and the radio boards causing high RF or other losses due to ground discontinuities.
Most prior art wireless networks include a third party wireless module and/or a radio module, which are not designed with intrinsic safety considerations in mind with respect to an antenna port. Additionally, such devices and components do not meet the required higher level of intrinsic safe requirement to acquire an explosion proof product certification (e.g., ATEX & IECEx). Such prior art devices also typically cause reductions in the transmission of power and the receiver sensitivity of the wireless module by reducing the transmit power by approximately 3 dB. This affects the free space range of the wireless module by halving the range and their reliability.
Based on the foregoing, it is believed that a need exists for an improved intrinsic safe in-line adaptor with an integrated capacitive barrier and method for connecting a wireless module with an antenna, as will be described in greater detail herein.